G15CS Front Fork Question

Information relating to the Matchless G15 or AJS Model 33 750cc twin. This also includes the G15 Mk II and the G15/45
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Ludwig
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G15CS Front Fork Question

Post by Ludwig »

Hello,
last weekend I dismantled the fork legs of my 1966 G15CS to fit new damper rods.
And to my surprise I found that the "new" rods are about 3" too short.
As the cross reference (MASTER PARTS LIST 1966 1967 1968 for 650SS, Atlas, G15CS..)
says that all types use the same rod, I think, the modified rods together with the long spacer
between spring and damper where used to fit an Atlas damper into the longer G15 fork.

http://i254.photobucket.com/albums/hh11 ... empfer.jpg

The damper's order number for the G15CS (030037) is the same as for all post 64 HW models.
My hope is, that this damper is about 3" longer that the damper shown in the photo.
So, with an correct damper it should be possible to omit the spacer and to use the original rod.
But I'm not sure, as I don't know the size of the dampers.
Can anybody help?
Thanks, regards
Ludwig
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John Donne
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G15CS Front Fork Question

Post by John Donne »

The only difference between the stock Atlas forks and the 1966 fork internals, are the dampers tubes 030037, and the fork stauntions which are 25 inches long, all the rest of the parts are as 650ss, and Atlas. The earlier 1964 Atlas Scrambler type machines had allot of different fork internals. The damper assembly was taken from the G80CS and the fork stauntions, had a screwed in steel bush, and outside springs. These springs were changed to a different type of out side spring for 1965. There was also listed in the 1965 supplement an adapter of about 3 inches long that screwed into the damper rods. This i suspect was made after the forks kept bottoming in the dampers. I also suspect it would have been suggested by Berliners in New York. This modification was listed in a Berliner service release in 1965.Mike Partridge of Walridge Motors in Canada was going to get the G15 type dampers reproduced. The G15 dampers are an inch longer than the stock Atlas ones if this helps.
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Ludwig
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G15CS Front Fork Question

Post by Ludwig »

Thanks, John.
Your information brings some clarity into the confusion.
Christian Gyde
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G15CS Front Fork Question

Post by Christian Gyde »

My September 1965 G15CS has outside springs and a top extension to the damper rods to accommodate the longer assembly. Wish I had taken some photos of the differences I found to the 1966 G12 roadholder I had in bits at the same time.
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John Donne
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G15CS Front Fork Question

Post by John Donne »

The difference between the G15CS internal dampers, and the later Roadholder derived dampers is the G80CS dampers have a circlip that hold the damper valve in place, and the Roadholders have a screw on cap. The earlier G15CS & N15CS had the G80CS fork damper assembly placed inside the Roadholder fork assembly. The adapters were added to the top of the damper rods. Mick Hemmings at Hemmings Motorcycles in Northampton supplies an adapter for the stock roadholder damper rods. Accessory Mart or Dommiracer in Cincinatti may still supply these adapters for the G80CS damper rods, for the earlier Atlas Scrambler forks. It is a very little know modification for these forks. The first P11's the single seat high pipe models also used the G80CS fork internals.
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Ludwig
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G15CS Front Fork Question

Post by Ludwig »

Ordered two 3/8" steel rods to make longer damper rods.
Not original, but I hope it's a proper solution.
Thanks again.
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John Donne
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G15CS Front Fork Question

Post by John Donne »

The solution would be to obtain the correct length dampers or modify your ones, by adding an extra inch to your exsisting ones. If AMC wanted to save money they would have used longer damper rods, but they made new dampers so this would be the way to go. All the post 1966 onwards fork internals for the CS, CSR, and Mk2 models all had the same fork internals. The G15CS was more of a street scrambler by then and not so much an off road racer, or desert racer. This was taken up by Norton's P11 models, a machine much more suited to off road riding and racing.
mdt-son
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Re: G15CS Front Fork Question

Post by mdt-son »

While on the subject of Norton-type front forks, does any of you know if the set of yokes 030026/030027 is identical for Norton and Matchless lines of models?
I know the spares list say they are identical but can I rely on this information?

When it comes to forks and frames, there were a lot of subtle modifications and not all are well documented.

TIA

Knut Sonsteby
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Re: G15CS Front Fork Question

Post by ManxmanGP »

I have two pairs of dampers tubes here; one pair of tubes is 10-3/4" in length overall and the other tubes are 8-7/8" in length overall... I believe the short set are good for the Norton "short" roadholder forks?
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